Drill attachment



Feb. 21, 1967 c. c. KoELN DRILL ATTACHMENT Filed July 3l, 1964 iig 3,305,034 DRILL ATTACHIVIENT Carl C. Koeln, 3830 Roland Blvd., St. Louis, Mo. 63121 Filed `Iuly 31, 1964, Ser. No. 386,700 2 Claims. (Cl. 175-299) This invention relates to churn drills.

Churn or cable drills are well known. Chu-rn drilling equipment normally consists of a cutting tool or drill, attached to a cable, which in turn is connected to a powerdriven rig by means of which the drill is alternately hoisted and abruptly dropped. This general type of drill and equipment is described in my Patent No. 2,524,707, and in patents to Green, No. 2,872,158, OConnor et al., No. 2,835,474 and Wentling, No. 1,504,999. Green and OConnor et al., provide examples of so-called double action or double blow drill attachments, to which this invention has particular application.

One of the objects of this invention is to provide a multi-blow churn drill attachment which is simpler in construction and more effective than such attachments known heretofore.

Other objects will become apparent to those skilled in the art in the light of the following description and accompanying drawing.

In accordance with this invention, generally stated, a multi-blow drill attachment is provided in which a plurality of hammers are mounted for axial movement within a casing, and are normally separated from a fixed anvil and from one another by springs which are graduated in stiffness or length or both, as a function of the superincumbent weight or the distance through which the hammers are expected to travel before impinging upon another hammer or an anvil.

The hammers are so arranged as to counter the tendency of the drill to rebound upon impact, with a series of successive blows of diminishing force.

In the preferred embodiment shown and described, three cylindrical hammers are slidably mounted on a shaft, one above the other, and all above a fixed anvil. The lowennost of the hammers is normally held spaced from the anvil by a spring capable of supporting the combined Weight of all of the slidable hammers; the second, center hammer is normally spaced from the lowermost hammer by a spring of a stiffness suicient to support the combined weight of the center and uppermost hammers, and' the uppermost hammer is normally spaced from the center hammer by a spring of a stiffness only suflicient to support the weight of the uppermost hammer. The supporting springs are helical springs, so positioned and arranged as to permit the lowermost hammer to impinge upon the anvil, the center hammer to impinge upon the lowermost hammer, and the upper hammer to impinge upon the center hammer successively when the entire drill assembly is dropped and hits bottom.

However, other embodiments will occur to those skilled in the art in the light of the following disclosure, For example, a series of plates may be used, each plate being supported by a spring of a size to support the superincumbent weight of the plates. Similarly, a series of tubes, telescoping one another, with separate springs for each tube, may be used.

In the drawing, FIGURE 1 is a view in side elevation, partly in section and partly broken away, of an illustrative embodiment of drill attachment of this invention.

Referring now to the drawing for one illustrative ernbodiment of drill attachment of this invention, reference numeral 1 indicates the entire attachment, which is provided at its lower end with a bit coupler 2 having a threaded socket 3 for attaching a bit, and at its upper 3,305,034 Patented Feb. 2l, 1967 end, with a shank coupler 4, with a threaded tapered stud 5, for attaching the drill shank.

The upper part of the bit coupler 2 is reduced in diameter to define a shoulder 12 and, above the shoulder 12, an anvil section 15. An annular channel 16 is provided in the side wall of the anvil section, In the center of anvil section 15, the bit coupler 2 is provided with an axially extending, shaft-receiving bore 18, and a spring seating counter-bore 19.

The shank coupler 4 is reduced in diameter at its lower part to define an annular shoulder 32 and, below the shoulder 32, a bumper section 30. An annular channel 36 is provided in the side wall of the bumper section 30. In the center of the bumper section 30, the shank coupler 4 is provided with an axial, shaft-receiving bore 38 and a rebound spring-receiving counter-bore 39.

A cylindrical casing 45 is securely mounted on the anvil section 15 of the bit coupler 2, at its lower end, with its lower edge abutting the shoulder 12. At its upper end, the casing 45 is securely mounted on the bumper section 30 of the shank coupler 4, with its upper end abutting the shoulder 32. The casing 45 is ordinarily sweated onto the couplers and peened into the channels 16 and 36. It may also be welded, since it must take the full weight of the drill.

Within the casing 45, a shaft 50 is mounted in and extends between the shaft-receiving bore 18 of the bit coupler 2 and the shaft-receiving bore 38 of the shank coupler 4. A helical bottom spring 52, mounted around the shaft 50, is seated at its lower end in the counterbore 19, and supports, at its upper end, a cylindrical bottom hammer 55. The bottom hammer 55 is slidably mounted on the shaft 50 by means of a central axially extending bore 56. A counter-bore 57 in the top of the bottom hammer 55 serves as a seat for a middle spring 60. The middle spring 60 bears against the underside of and supports a middle hammer which, in the embodiment shown, is of the same weight, size, and construction as the lower hammer 55. The middle hammer 65 has a bore 66, by 'which the hammer is slidably mounted on the shaft 50, and a counter-bore 57. An upper spring is seated with its lower end in the counter-bore 67, and with its upper end bearing on the bottom of and supporting an upper hammer 75. In the embodiment shown, the upper hammer is of the sarne weight as the hammers 55 and 65, and is provided with a centrally located axially extending bore 76, by which the upper hammer 75 is slidably mounted on shaft S0, but has no counter-bore.

A rebound spring 80, with its upper end seated in the rebound spring counter-bore 39, bears, with its lower end, on the top surface of the upper hammer 75.

As has been indicated, the lowermost spring 52 is of a size and stiffness to support the weight of all three of the hammers 55, 65 and 75, and of the springs 60, 70 and 80. The middle spring 60 is of a size and stiffness to support only the middle and upper hammers 65 and 75 and the springs 70 and 80. The upper spring 70 is of a size and stiffness only to support the hammer 75 and spring 80. Thus, by way of example, if the hammers 55, 65 and 75 weigh 30 pounds apiece, the lower spring 52 will be only a little more than a 90 pound spring; the springl 60, a little more than a 60 pound spring, and the spring 70 only slightly more than a 30 pound spring. The function of the rebound spring is not to exert a strong downward pressure on the hammers, but only to serve as a buffer, to minimize the upward impact of the rebounding hammers.

It is to be noted that the springs 52, 60 and 70 and the -counter-bores 19, 57 and 67 are proportioned to permit the lower surface of the hammer 55 to impinge upon the top surface of the anvil 15, the lower surface of the hammer 65 to impinge upon the top of the hammer 55 and the lower surface of the hammer 75 to impinge up- `on the top of the hammer 65 when the drill hits bottom gravity, toward the bit. yThe hammer 55 rst strikes the anvil 15, which stops its downward progress. The hammer 65 theny strikes the top of the hammer 55, which interrupts its downward progress, and the hammer 75 then strikes the top of the hammer 65. `The stiffness of the springs is such that the impa-ct of each of the hammers is transmitted to the drill bit through the anvil 15, hammer 55 and hammer 65 successively.

As was pointed out in the general description of the invention, numerous Variations in the construction of the device of this invention will occur to those skilled in the art in the light of the foregoing disclosure. The essential features of the invention are the provision of vertically superposed weights with interposed springs graduated in strength or length or both to provide, in a simple manner, a succession of hammer blows to the drill upon irnpact.

Having thus described the invention, what is claimed and desired to be secured by Letters Patent is:

1. A drill attachment for churn drills, comprising a vertically elongated casing adapted to be connected to suspending means at its upper end, vertically superposed hammers slidably mounted within said casing for axial movement therein, an anvil fixed at the lower end of said casing and adapted to be :connected to a bit, and springs mounted Vbetween said hammers and said anvil and between said' hammers respectively, said springs each having a stilness which is a direct function of the total superincumbent Weight on said spring whereby saidv spring supports the hammer immediately contiguous and above it in vertically spaced relation to the adjacent surface below said hammer when the attachment is at rest, and means for accommodating each of said springs in compression, with respect to its contiguous hammer,` whereby a lower surface of each hammer strikes directly the surface below it when the springs are compressed, and the hammers strike said surfaces serially from the lowermost to the uppermost.

2. A drill attachment for churn drills, comprising a vertically elongated casing adapted to be connected to suspending means at itsl upper end, a shaft mounted axial- 1y within said casing, three vertically superposed cylindrical hammers slidably mounted on said shaft, an anvil fixed at the lower end of said casing adapted to be connected to a bit, and helical springs mounted on said shaft, one between the lowermost of said hammers and the xed anvil, one between the center hammer and the lowermost hammer and one between the cente-r hammerand the uppermost hammer, said springs being of a yrelative stiffness on the order of three, two and one, respectively, and said springs being seated at at least one end in a counter-bore of a size to accommodate the spring when the spring is compressed, said springs being of a stiffness to maintain the hammers and the anvil and the upper and lowermost hammers and the center hammer in vertically spaced relation when the attachment is at rest.

References Cited bythe Examiner UNITED STATES PATENTS 2,017,470 lil/1935 Nliller 173--118 2,524,707 10/1950 Koeln 175--299 2,742,263 4/ 1956 Clugage 175-56 2,765,776 10/1956 Pyk 173-102 2,835,474 5/1958 OConnor et al. 175-299 2,872,158 2/ 1959 Green 175-299 3,215,212 11/1965 Bal'dWell 175`299 CHARLES E. OCONNELL, Primary Examiner.

R. E. FAVREAU, Assistant Examiner. 

1. A DRILL ATTACHMENT FOR CHURN DRILLS, COMPRISING A VERTICALLY ELONGATED CASING ADAPTED TO BE CONNECTED TO SUSPENDING MEANS AT ITS UPPER END, VERTICALLY SUPERPOSED HAMMERS SLIDABLY MOUNTED WITHIN SAID CASING FOR AXIAL MOVEMENT THEREIN, AN ANVIL FIXED AT THE LOWER END OF SAID CASING AND ADAPTED TO BE CONNECTED TO A BIT, AND SPRINGS MOUNTED BETWEEN SAID HAMMERS AND SAID ANVIL AND BETWEEN SAID HAMMERS RESPECTIVELY, SAID SPRINGS EACH HAVING A STIFFNESS WHICH IS A DIRECT FUNCTION OF THE TOTAL SUPERINCUMBENT WEIGHT ON SAID SPRING WHEREBY SAID SPRING SUPPORTS THE HAMMER IMMEDIATELY CONTIGUOUS AND ABOVE IT IN VERTICALLY SPACED RELATION TO THE ADJACENT SURFACE BELOW SAID HAMMER WHEN THE ATTACHMENT IS AT REST, AND MEANS FOR ACCOMMODATING EACH OF SAID SPRINGS IN COMPRESSION, WITH RESPECT TO ITS CONTIGUOUS HAMMER, WHEREBY A LOWER SURFACE OF EACH HAMMER STRIKES DIRECTLY THE SURFACE BELOW IT WHEN THE SPRINGS ARE COMPRESSED, AND THE HAMMERS STRIKE SAID SURFACES SERIALLY FROM THE LOWERMOST TO THE UPPERMOST. 